Synthesis,Structure And Physicochemical Properties Of Energetic Complexes Based On 1,3-bis(5-tetrazolyl) Triazene

The increase of energy of traditional energetic materials is often accompanied by the decrease of sensitivity,energetic coordination polymers(ECPs)can effectively make up for this deficiency because they are composed of energetic organic ligands and metal central ions,nitrogen-rich compounds as energetic organic ligands make their energy controllable and metal central ions make their sensitivity controllable.According to the theory of coordination chemistry,this paper innovatively introduces triazene group as the linker of ligand,based on the nitrogen-rich heterocyclic ligand 1,3-bis(5-tetrazolyl)triazene(H₃BTT)self-assembled with lead ion,manganese ion and zinc ion,six cases of ECPs were generated:{[Pb₂(HBTT)(O)(H₂O)]·H₂O}_n(1),{[Pb₂(HBTT)₂(H₂O)₇]·H₂O}_n(2),[Mn₃(BTT)₂(H₂O)₈]_n(3),{[Mn(BTT)(H₂O)₂]·0.5(C₂N₂H₁₀)}_n(4),{[Mn₂(HBTT)₂(H₂O)₄]·2H₂O}_n(5),{[Zn(HBTT)(H₂O)₂]·H₂O}_n(6).On the basis of H₃BTT in-situ decomposition reaction and calorimetry theory,a case of ECP[Zn₂(ATZ)₃(N₃)·2H₂O]_n(7)with azide anion and 5-amino tetrazole as ligands and zinc ion as metal center was obtained by using C80microthermometer to monitor the reaction desorption heat.It is proved that all seven ECPs have the potential for use as high-energy density materials and can have accelerated effects on the thermal decomposition process of ammonium perchlorate(AP)and hexogen(RDX).(1)By X-ray single crystal diffractometer,infrared spectrometer and elemental analysis,the crystal structure of sewen ECPs were obtained.The purity of the sample was investigated by X-ray diffractometer.The results show that ECPs 1,3 and 4 are one-dimensional chain structures,ECPs 2 and 7 are two-dimensional layered structures,ECPs 5 and 6 are three-dimensional frame structures.Combined with the analysis of synthesis conditions,the low temperature conditions are more favorable for the formation of ECPs.The change of alkaline reagents can change the structure of ECPs,the addition of heterometals may play the role of template agents,and the angle torsion of tetrazole rings can be used to construct the multidimensional ECPs.(2)TG-DSC curves of seven ECPs were obtained by thermogravimetric analyzer and differential scanning calorimeter.Comparing the results with the single crystal structure,we know that the participation of triazene in coordination is easy for metal ions to ring through coordination bonds,which hinders the further extension of the structure,but increases the stability of the ECPs,the TG curves show that the angle is close to 90°steps,which is beneficial to the concentrated release of energy;when the triazene does not participate in the coordination,it will play the role of extending the structure.The ECPs obtained are three-dimensional structures,although similar to the thermal decomposition process of the ligand,it presents a slow decomposition process and no obvious steps appear,however,because of the three-dimensional frame structure and the existence of hydrogen bonds,it has an exothermic temperature higher than 300?.(3)Based on Kissinger and Ozawa-Doyle methods,the thermodynamic data of the decomposition process of target ECPs are calculated.Based on density functional theory and Kamlet-Jacobs(K-J equation),the detonation heat,detonation velocity and detonation pressure of seven ECPs are estimated.The results show that the detonation performance of ECPs 1 and 2 is better.A BAM friction sensor and an impact sensor were used to test the friction sensitivity and impact sensitivity of the target ECPs.The results showed that the ECPs 1-7 showed stunning characteristics.(4)The catalytic properties of seven ECPs on the thermal decomposition process of AP and RDX were studied by DSC method.The DSC curves of seven ECPs and AP?RDX mixtures were obtained.Compared with the absorption and exothermic peaks on the DSC curves of pure AP and pure RDX,seven ECPs advanced the thermal decomposition temperature of AP and RDX,showing a positive acceleration effect on their combustion process.